The task of system automation deals with the definition and execution of operations conducted by a machine or a technical industrial process. For this purpose, the system subject to automation, such as, e.g., a chemical reactor system, an automotive-function test rig, or an analytical instrument hereinafter termed plant or process to be controlled, is typically connected to at least one actuator unit, hereinafter termed actor unit, and at least one sensor unit, wherein the at least one sensor unit collects and outputs information about the plant to a controller, and the controller calculates based on received information a control signal and outputs the control signal to the at least one actor unit connected to and controlling the plant.
The respective actor unit may comprise an actuating element such as, for example, a valve, a pump or a heater, but may further comprise a distributed controller which regulates a setting of the respective actuating element at a predefined setpoint value. As such, the abovementioned controller of the automated system may be configured to output a control signal to the at least one actor unit in the form of a setpoint value, wherein the respective setpoint value represent a desired level of a value to be regulated using the respective distributed controller.
Also, the respective sensor unit may comprise a sensor element such as, for example, a thermo element, pressure sensor or pH sensor, but may further comprise estimation or filtering components used to filter the data collected by the respective sensor element, in order to improve the quality of the sensor signal or to estimate a state of the automated system by using state observer structures, such as Kalman filters or other types of dynamic filters known in the art. In this sense, the respective sensor unit collects and outputs information about the plant to a controller.
The automated system may comprise a simple or complex machine or technical process, connected to a controller unit via at least one actor unit and at least one sensor unit, and is designed and implemented to perform the task of executing some type of predefined operations, for example:                A chemical reactor system may comprise sensor units with sensor elements such as thermo elements, pressure sensors or pH sensors, and actor units with actuating elements, such as valves, pumps, heaters, to name a few possibilities, wherein the task of the automated system may relate to chemical synthesis.        An automotive-function test rig may comprise a number of different sensor and actor units applied in the automated system to verify or test the performance of an automotive component.        An analytical instrument may comprise different sensor and actor units applied in an automated laboratory test equipment to determine the properties of a object or organical or inorganic compound or mixture. The properties can be chemical composition, or some physical property, or the effect the test object or compound or mixture has on another object, compound or mixture.        
The controller of the automation system comprises a computing processing unit for performing calculations and possibly logical decisions, to decide how individual components, such as the actor units of the automated system, should change their settings over time. If such decisions are based on measured sensor values, the controller is said to be implemented in a closed-loop constellation, whereas decisions made in an open-loop controller are independent from any such sensor value.
It follows that the automated system executes some type of operations to fulfill a desired task, wherein the order and structure of operations is typically defined in some sequential form. Such sequences are defined in a manual or automated manner such to operate the automated system, i.e., the controller thereof, in accordance with the task involved. The so-called sequencers simplify the work of defining and applying such appropriate sequences of operations, and may be used and instructed by the operator by means of an, e.g., sequence script, sequence table or a highly configurable sequence control user interface. In this regard, the sequence information used to instruct the sequencer comprises a list of consecutively arranged operations defined as steps which are interpreted one after another by the sequencer, see, e.g., the linear scripted sequence illustrated in FIG. 1. A step usually consists of a statement to perform an action, a possible set of input parameters to customize those actions, and possibly an output value of some kind. It follows that the statement may, e.g., refer to a general software function or method. In this regard, the sequencer can be seen as an interpreter and builds a part of the automated system.
For example, the document WO 03/054561 refers to a transformer test sequence editor that enables a tester to implement test sequences with adjustable test parameters. In this regard, a test sequence engine enables a tester to perform sequences of tests and an automated test sequence editor allows the editing of the test sequence to be performed. It follows that test instructions are executed in accordance with the order provided in the edited test sequences.
However, as it is often desired to have operations run not only in a sequence but also in parallel in automated systems, take for example the task of simultaneous calibration of different machine parts, it would clearly be advantageous for the human operator of the automated system to have simple means to instruct the system and execute multiple operations in parallel. However, information received by prior art sequencers do not provide for defining operations to be executed in a parallel manner, and the operator is left with the choice between a suboptimal and time-consuming sequential execution of steps, or with the option of requesting a system integrator, e.g. the person or provider who supplied the sequencer, to use his expert know-how and advanced programming skills in, e.g., C++, Basic or Labview to program a tailored parallel calibration subroutine. By this way, the operator is barred from quickly implementing new ideas of parallel operations, and is forced to involve the system integrator and accept the respective incurred development time, costs and other inconveniences.